Waste Recovery through Thermochemical Conversion Technologies: A Case Study with Several Portuguese Agroforestry By-Products

Agro-forestry waste management- A review

Agroforestry, an integration of farming system with woody perennials leads to the generation of potential agroforestry residues. The conventional treatment of agroforestry waste includes landfilling, thermal management, and decomposition which is accompanied with their own share of disadvantages. The ample amount of residues and products needs effective management to reap the economic and environmental benefits. The channel of waste collection, transportation, and recycle or valorization into products like biofuel, fertilizers, biochar, industrial chemicals is essential to maintain a circular sustainable bioeconomy. Global market value of biowaste to bioenergy (BtB) technology is roughly US $25.32 billion and is projected to enhance to US $40 billion by 2023. Employment of an appropriate pretreatment technology such as fermentation, hydrolysis, gasification etc. is going to elevate the degree of valorization along with surpassing the mobilization barrier. The sustainability assessment of the management process can be achieved with multiple models including technoeconomic analysis, life cycle assessment and multi criteria approach which are dependent on both hard and soft indices. Additionally, the loopholes of the agroforestry sectors would be managed by the introduction of appropriate policies which are undertaken globally by the Orlando and Lugo declarations, food and agriculture organization, Millennium Development Goals, Global Research Alliance and Guidelines for Sustainable Agriculture and Rural Development. The present review envisaged the agroforestry waste management strategy and its sustainability assessment primarily based upon Social, Economic and Environmental parameters without tormenting the future generations.

Evaluation of the Potential of Agricultural Waste Recovery: Energy Densification as a Factor for Residual Biomass Logistics Optimization

The use of residual forms of biomass, resulting from processes of transformation of the agri-food and/or forest industries, presents itself as an alternative with high potential for energy recovery, given the existing availability, both from the perspective of quantities, but also from the perspective of geographic distribution. In this work, samples of four by-products originating from the agri-food industry were collected, namely coconut shells, sugarcane bagasse, cashew nutshells, and palm kernel shells, which were characterized in the laboratory by determining their Thermogravimetric and Elemental analysis, subsequently calculating the High Heating Value, Low Heating Value, Hardgrove Grindability Index, Mass Yield, Energy Yield, and Energy Densification Ratio. The values obtained show the potential to optimize logistical operations related to transportation, demonstrating that energy densification operations, especially if associated with physical densification processes, enable the use of these residual forms of biomass in the replacement of fossil fuels, such as coal.